The present invention relates to an apparatus for washing and cleaning the external surface of an airplane.
Airplanes, particularly large-size passenger airplanes, should have their attractive appearance well maintained. The external surfaces of such airplanes should be kept as clean as possible to minimize air resistance and, hence, fuel consumption. The cleaning of the external surfaces is necessary also for the purpose of preventing rusting of the plates which constitute the external surface to ensure safety and longer life of the airplanes.
The contamination of external surfaces of airplanes is unavoidable because the sticky components of the exhaust gases from the engine stick to the external surface and because the dust and other particles suspended in the air often penetrate the surface coating of the airplane.
In order, therefore, to maintain the attractive appearance of the airplane while achieving the prevention of rusting and fuel saving, it is necessary to conduct washing and cleaning of the external surface of the airplane periodically.
At the present stage, the washing of airplanes is conducted by manual labor. Although proposals have been made for the mechanization and automation of the cleaning work, none of these proposals has been put into practical use.
These known proposals have the following features:
(1) The washing apparatus is situated on the ground, i.e. at the same level as the airplane.
(2) The washing apparatus has a plurality of washing units which operate independently. These units are arranged to clean different portions of the airplane, such as the nose, tail, main wings and tail wings of the airplane. In some cases, separate units are used for washing the upper and lower sides of the main wings, respectively.
(3) Various measures are taken to bring the washing means such as brushes into contact with the airplane. For instance, the washing means are movably mounted to the stationary structure of a building into which the airplane is taxied, and the washing means are then moved along the airplane. Alternatively, the cleaning means are mounted on a crane or vehicle which can approach and move along the airplane while it is stationed at an apron for washing.
These proposals suffer from the following common disadvantages.
(1) Since the washing apparatus is situated at the same level as the airplane on the ground, it is quite difficult to allow sufficient space or height, particularly for the washing unit for washing the lower side of the airplane, although a sufficient space may be provided for the washing unit which cleans the upper side of the airplane. Consequently, the washing unit for the lower side of the airplane has only a small adaptability to the configuration of the lower side of the airplane, as compared with the unit for washing the upper side of the airplane. In some cases, the washing unit cannot access the lowermost part of the body of the airplane where the clearance above the ground surface is very small.
(2) The use of independent washing units for various parts of the airplane has been proposed as a solution to the problem encountered in adapting a single or several washing means such as brushes to various parts of airplanes having various configurations. If such a difficulty could be overcome, it would be preferable to reduce as much as possible the number of the washing units from the view point of economy, saving of human labour and simplification of the whole apparatus.
(3) When a multiplicity of washing units are used in a house or the like, the house must be of a huge size with an impractically large span between supporting pillars, because the building has to accomodate a multiplicity of washing units, as well as an airplane which is very large. The large span between the pillars necessitates higher rigidity of the beams and girders of the building structure. Thus, this proposal requires an impractically large financial investment. The use of a plurality of washing means carried by mobile carriers accessible to an airplane, e.g. cranes or trucks, also suffers from the problem relating to the difficulty in washing the lower side of the airplane as mentioned in (1) above, as well as the necessity for a multiplicity of washing units as mentioned in (2) above. Moreover, it is difficult to automate the cleaning work with a multiplicity of cleaning units carried by a crane or trucks and, accordingly, the effect of cleaning unfavourably depends on the skill or experience of the operator.